The research involved monitoring 231 type 2diabetes patients, 149 of which had obstructive sleep apnoea (OSA), a sleep disorder resulting from disturbed breathing. They showed there were 48 per cent of those with eye damage in the OSA group, as compared with only 20 per cent in the group without OSA.

In separate research, which examined 230 people with type 2 diabetes - of which 148 also had OSA - 60 per cent of the group with OSA were shown to have nerve damage as compared with 22 per cent in the group without OSA.

Iain Frame, director of research at charity Diabetes UK, commented "It's not new to say that many people with Type 2 diabetes have this sleeping disorder, but it is the first time we've seen researchers look at a link between this sleeping problem and damage to eyes and nerves suffered by some people with Type 2 diabetes."

He added "It seems that people with Type 2 diabetes could be more at risk of those complications if they have trouble sleeping than if they don't."

For both pieces of research, factors such as age, gender, ethnicity, blood pressure, cholesterol, blood sugar levels and smoking were taken into account when assessing the link between diabetes and OSA.